Short Notes in Plastic Surgery

August 16, 2013

36. Fractures of the Maxilla

Filed under: Chapter 36,Uncategorized — ravinthatte @ 5:55 am

36. Fractures of the Maxilla

1.   Anatomy:  The two maxillary bones are shaped like pyramids and they together form what we clinically call the maxilla. Each maxillary bone has four processes. The frontal process skirts the lateral side of the nasal bone to which it is firmly attached and is superiorly joined to the frontal bone. This attachment is very strong. The zygomatic process of the maxilla forms the medial one third of the orbital floor and it is to this part that the canthal ligament is attached. The articulation of this process to the zygoma is solid. The palatine processes of the two maxillary bones on either side join in the midline to form the anterior two-thirds of the hard palate. The alveolar process of the maxilla accommodates the upper teeth and the two alveolar processes together form the upper dental arch. Behind, in the oral cavity, the palatine processes of the maxillae are attached to the palatine bone (its horizontal part) and the vertical part of the palatine bones in turn are in close approximation to the pterygoid plates of the sphenoid and that forms the maxillary connection to the base of the skull (Fig. 1,2,3).

Slide1

2.   The maxillary bones are surrounded by strong bony buttresses in the form of its connections with the body of the zygoma on the lateral side, its frontal connection superiorly and its thick alveolar part inferiorly which abuts against the mandible. The indirect posterior connection through the palatine bone with the pterygoid plates (of the sphenoid) constitutes the buttress below the base of the skull. Within this circle of buttresses lies a hollow part in the anterior part of the maxilla, the maxillary antrum, which opens under a ridge called the middle concha which is a part of the maxilla. A groove between the nasal bones medially and the frontal process of the maxilla laterally is occupied by the naso-lacrymal duct which enters under the inferior concha which is sometimes considered a separate bone and is firmly attached to the maxilla proper. The two maxillary bones enclose the lower two-third of the nasal cavity, the upper one third being enclosed by the nasal bones (Fig. 4).

Slide2

3.   Fractures of the maxilla: It is customary to describe fractures of the maxillary bones in three categories as described by Le Forte a century ago and the classification’s utter logic was such that no other classification has replaced it.  It must be added that this classification is really a description of fractures around the middle third of the face and gives a territorial description of fractures of and around the maxilla. The classification employs three distinct planes.

4.   The first and the most inferior is the Le Forte 1 fracture, the line of which passes above the alveolar process and travels backwards and the fracture includes the area between the horizontal and vertical part of the palatine bone up to the pterygoid plates (Fig. 5). It therefore runs across the nasal cavity. Such a fracture might be incomplete and unilateral (Fig. 6). See below.

Slide3

The Le Forte 2 fracture is pyramidal in shape. The fracture line begins at the pterygoid plates travelling upwards medially to include the medial third of the orbital floor and then joining at or around the root of the nose. This fracture is more of a disjunction between the maxillary bones from the zygomatic bone laterally, the frontal bone superiorly and its sphenoidal connection posteriorly. The alveolar and the palatine processes remain intact within the fractured segment (Fig. 7). The fracture can be incomplete and on one side of the face (Fig. 8), see below.

Slide4

The Le Forte 3 fracture is not really a fracture of the maxilla but a disjunction of the maxillary and the zygomatic bone and the sphenoidal part of the orbit from the skull (Fig. 9).

Slide5

While the Le Forte classification is well set, clinically a combination of fractures can occur in this area because the nature of impact may vary. A sagittal fracture on one side is not uncommon and includes the Le Forte 1 and 2 territories (Fig. 6 and 8). The palatine processes of the maxilla in this kind of a fracture are separated at the fracture line and if the mucosa is torn the nasal and oral cavity will have a communication between them.

5.   Associated injuries and consequences: Fractured segments in the middle third of the face classically move downwards and backwards (posteriorly). The latter gives the face its dish like appearance but it is the inferior movement which gives it an elongated appearance (Fig. 10) and this stretches the soft tissues with it. A delay of several days in the treatment of these fractures will mar the aesthetic results because the soft tissue envelope of the facial bony skeleton is so snugly draped over the individual bones that it rarely recovers to its original when the bony parts are not fixed early.

The forces which cause the fractures are usually of a high velocity and can do damage to surrounding bones as well as injuries to other parts of the body. Fractures of the skeleton, intra-abdominal injuries or fractures of ribs with intra-thoracic complications must be looked for. Airway obstruction is not uncommon and the patient may be in shock. Equally important, the skull might be fractured (Fig. 11) with intra-cranial bleeding, the signs of which must be looked for and any clear nasal discharge should arouse suspicion of CSF rhinorrhoea. The orbit and the eye need particular attention.

6.   Diagnosis: Unlike fractures around the orbit or the nose where the loose palpebral skin fills up rapidly and is marked by ecchymosis the Le Forte fractures exhibit only moderate oedema unless the fracture lines pass through the orbital floor or the nose (Fig. 10). The classical feature of these fractures is the anterior open bite with the upper molars having descended abnormally  not allowing the anterior dental arch to close over the mandibular teeth. A bimanual examination with the index finger in the mouth and the thumb over the alveolar process can easily elicit a rocking movement of a part or whole of the maxilla in relation to the other bones or the skull. A crepitus might also be heard. An external digital examination might reveal gaps or steps in the bony contour. An oral examination frequently reveals torn mucosa, haematomas under intact buccal mucosa or sharp bony points at fracture sites. It is to be noted that in Le Forte 3 types of high fractures the descent of the whole of the middle third of the face occurs without a posterior and inferior tilt and the occlusion might remain normal. The advent of three dimensional computerized tomography has made the diagnosis and the nature of these fractures not only easy but precise. Old plain radiographs done with great skill are probably not done in many centres anymore and eponymous techniques such as Water’s or Caldwells’ views or the submento-vertex views may soon become historical notes. When a CT-scan is obtained it is always advisable to include the skull in the investigation and to also ask for coronal and sagittal views to demonstrate the nature of displacement of individual bones.

Slide6

7.   Treatment: The patient should be fully stablised hemodynamically prior to the surgical treatment of these fractures. Intra-cranial lesions such as cerebral oedema (sub-arachnoid hemorrhage) sub-dural or extra-dural hematomas take precedence in treatment. Occasionally if the patient is fit, fixation of skeletal fractures may be done in the same sitting if the anaesthesiologists give their consent. Quite a few of these patients may have had a tracheostomy because in the initial phases of the treatment the airway may have been compromised due to bleeding or because of intra-oral and nasal swelling. Such a tracheostomy is allowed to remain because in major fractures both oral and nasal intubation would need to be done one after the other to help fix individual bones and perform inter-maxillary fixation (see Fig. 13 to 17). A tracheostomy avoids these cumbersome changes.

That maxillo-facial fractures cannot be fixed with external plasters as for example in the limbs has always been a given for a very long time. This problem has been sorted out in the case of fractures of the face by taking help of the next unfractured stable bone, for example, the mandible below or the skull above. In a Le Forte 1 fracture for example, after reduction and restoration of normal dental occlusion the maxillary segment can be fixed to the mandible by wires or arch bars (see next chapter, Fractures of the Mandible for the technique of inter-maxillary fixation). The higher fractures could be fixed to the skull also with wires. Wires were also used to fix fractured individual segments of bones. Occasionally in the distant past, a plaster turban with embedded metal parts was used to suspend and fix these fractures with the help of subcutaneous wires or external appliances. The introduction of plates and screws of titanium of varying sizes has now overcome these cumbersome methods with an added advantage in that plates do not allow any rotational movement in the fixed fragments which wires were not successful in preventing (Fig. 13-17).

Slide7

Slide8

In almost all these fractures which show some comminution cancellous bone grafts are placed in the area of natural buttresses. Representative red arrows are shown in figure 15 as an example.

8.   Access: The surgical treatment of the fractures of the maxillofacial skeleton and particularly for the middle one third of the face is done through a variety of incisions. The bicoronal incision can take care of trephining holes in the skull for craniofacial suspension and can reach up to the body of the zygoma and the lateral one third of the orbit and also allows access to the upper half of the nose (Fig. 19 and 21). The transconjunctival approach allows access to the whole of the inferior medial and lateral wall of the orbit (Fig. 20). An intra-oral incision through the superior sulcus enables the surgeon to reach the maxillary bones in almost their entirety (Fig. 18). In all the above scars remain hidden. Wounds on the face which accompany some of these injuries and which may be located over bony parts which are to undergo fixation can be used as an access. These wounds might be extended judiciously parallel or within the direction of the tension lines (see figures below).

Slide9

Post-operative care

Many a time, the actual inter-maxillary fixation is finally effected (after the arch bars have already been fixed) only after the patient comes out of anaesthesia to prevent choking due to the tongue falling back. A tongue stitch is frequently employed and brought out through a gap in the teeth. This is necessary because the tissue surrounding the oro-nasal airway is frequently swollen and is already compromised. Oral hygiene needs special attention. Brushing is permitted after the first two days and because only fluids can be taken during the duration of inter-maxillary fixation nutrition needs to be closely monitored. When plates and screws are used, inter-maxillary fixation may be removed as early as three or four weeks but if the fractures are comminuted, the additional support of the mandible helps in the healing of fractures.

Acknowledgments

The compiler of these notes thanks Nitin Mokal, Nisheet Agni and Arunesh Gupta for the illustrations. The figures of the skull are actual photographs and the idea of the fracture line has been borrowed from standard textbooks.

Blog at WordPress.com.